This invention relates to a hydraulic coupling device for hydraulically coupling a multi-line hose to a connector having a plurality of sockets. The invention is particularly useful in the hydraulic distribution systems used in underground mine workings, particularly for hydraulically advanceable mine roof support assemblies and other hydraulic appliances.
Systems are known in which numerous hydraulic lines are bunched together to form multi-line hoses which are interconnected by means of generally cylindrical plug couplings. A known plug coupling of this type includes a coupling device having a plurality of plug pins, and a connector having a plurality of sockets which mate with the plug pins, the coupling device and the connector being attached to respective multi-line hoses. The coupling device is provided with an alignment pin which mates with a corresponding aperture in the connector to ensure accurate alignment of the plug pins and the sockets. With this type of plug coupling, it is usual to bunch together only the pressure and control lines to form multi-line hoses, while the hydraulic return line (which is of larger diameter than the pressure or control lines) is laid as a separate line. The provision of this separate return line is disadvantageous in that it leads to additional expense, not only for the return line itself, but also for the additional couplings which are necessary to connect the return line to the various hydraulic appliances. Moreover, such a system having two sets of hoses takes longer to assemble, and occupies more of the valuable space in a mine working, than systems utilising only one hose for supply and return of pressurised hydraulic fluid.